The development of chicken palatal taste buds was studied by means of tritiated thymidine autoradiography. Chick embryos were injected with tritiated thymidine in ovo and sacrificed at 5-day intervals from embryonic day 21 to post-hatching day 2. Palatal tissue was fixed and processed for electron microscopy, then thick sectioned at 4 micrometers and examined in the light microscopy, then thick sectioned at 4 micrometers and examined in the light microscope to locate the taste buds. The thick sections were re-embedded and sectioned at .25 micrometers, then processed for EM autoradiography. After exposure times of 3 to 6 weeks, the .25 micrometer sections were examined with the HVEM to locate labelled taste bud cells and to characterize these cells.